This study is a randomized, double-blind, placebo-controlled clinical trial designed to evaluate the effects of astragaloside supplementation on joint discomfort in healthy adults. The primary goal is to determine if daily intake of astragaloside can improve knee joint function and reduce discomfort over a 12-week period. Participants will be randomly assigned to receive either an astragaloside capsule or a placebo capsule once daily. Aim to see if those taking astragaloside experience better mobility and fewer joint-related symptoms compared to those in the placebo group.

The purpose of this randomized, double-blind clinical trial is to investigate the efficacy of astragaloside supplementation in enhancing joint health and physical function among healthy individuals aged 20 to 70 years.

Study Design and Procedures: Participants will be randomized into two groups: the intervention group (astragaloside) and the control group (placebo). Each participant will be instructed to consume one capsule daily after a meal for 12 weeks.

The study aims to address the following objectives:

Physical Function Assessment: To evaluate changes in knee joint mobility and strength using the Single-Leg Step-Down (SLSD) test and Range of Motion (ROM) measurements.

Subjective Symptoms and Quality of Life: To assess improvements in knee-related symptoms through the Knee Injury and Osteoarthritis Outcome Score (KOOS) questionnaire.

Biological Markers: To analyze blood biomarkers related to joint health and systemic response.

Comparative analysis between the astragaloside and placebo groups will be conducted to determine the statistical significance of the supplement's impact on joint function and discomfort.

Inclusion Criteria:

• Healthy male or female adults, aged 18 to 75 years, with a body mass index (BMI) of 18-30 kg/m².
• Actively participates in regular exercise, including but not limited to soccer, basketball, tennis, rugby, running, or cycling, and engages in at least two training sessions per week during the study period.
• Experiences pain ≥5 on a Visual Analog Scale (VAS) during the Single-Leg Step-Down (SLSD) test when performing 30 to 150 steps.
• Has experienced knee discomfort within the last 3 months during or after physical activity.

Exclusion Criteria:

• Participation in another clinical trial within 30 days prior to study enrollment.
• Uncontrolled diabetes or currently using insulin therapy.
• Current smokers.
• History of heart failure.
• Previous bilateral knee replacement surgery.
• Current use of prescription COX-2 inhibitors, chondroitin sulfate, glucosamine sulfate or hydrochloride, collagen, fish oil, or vitamin D supplements and unwilling to discontinue these during the study.
• Likely to be lost to follow-up, non-compliant, or requiring concomitant medication that may interfere with study outcomes.
• Received intra-articular treatment within 3 months prior to study start.
• Medical conditions that may interfere with study results, such as cancer, cardiovascular disease (e.g., stroke, myocardial infarction), pregnancy, or breastfeeding.
• Hip, spine, or foot injuries that could affect study outcomes.